C & Objective-C

Any C code is valid Objective C code, but to write an iPhone app you may need to learn the basics of Objective C since most of the API is for Objective C.

But the documentation from Apple is very good and easy to follow.

 

Stating the obvious but Objective-C is object-oriented while C is procedural, so those are two really different beasts and the programming "mindsets" are really, really different.
Even visually, a Code written in Objective-C doesn't really strike as being a subset of C.

 

You may not have noticed, but C is indeed a subset of Objective-C, not the other way round. And C++ is a subset of Objective-C++, which people use a lot as well (useful if you want to display a std::string in a UI object). Many of the more stupid questions about Objective-C come up here because people don't know the C language, so they have no idea what "*" or heaven forbid a "**" in Objective-C code means.